Producer group OPEC on Tuesday became the latest forecaster to bump up global oil demand estimates.

U.S. crude jumped 71 cents to $74.86 a barrel by 4.51 a.m. EDT, after surging to $75.15, the highest this year, earlier in the session. Brent crude rose 63 cents to $73.03.

There's a lot of positive sentiment right now, but that's largely driven by the softer dollar, said Mark Pervan, senior commodity strategist at ANZ Bank in Melbourne.

Whether the rally is sustainable depends on further dollar weakness. If there is, we could head toward the $75 to $80 range, but $75 would be a key resistance level.

Gold hit a record high on Wednesday, also supported by the dollar, which is under pressure from expectations of low interest rates. Dollar weakness makes oil and bullion more affordable for non-dollar holders.

Analysts who use past price moves to predict future direction said a further rally would depend on U.S. crude, also known as WTI, closing above $75 a barrel, which has been a key resistance level.

The advance in WTI is in our view purely technical and dollar linked -- hence reversals can be sharp when and if the dollar stops to fall off the cliff, said Olivier Jakob, analyst at Petromatrix.

Earnings are due from a number of major U.S. firms this week, and the oil market is tracking corporate results closely for signs of a broad economic rebound.

Tech bellwether Intel Corp's quarterly outlook and results shattered expectations on Tuesday, boosting its shares and fuelling optimism over a wider recovery in the sector.

Cold weather in the United States has also supported prices. Heating demand will be higher than normal this week, the National Weather Service said on Monday.

U.S. inventory data from the American Petroleum Institute, due later in the session, will offer a further clue on the pace of demand recovery in the world's largest economy.